Various medicine packaging apparatuses have been provided which prepare continuous medicine bags or dose packages by packaging medicine such as a tablet and powdered medicine per dose (as one medicine bags) based on prescriptions. Some of these devices use package sheet rolls on which a long and narrow package sheet previously folded into two in the longitudinal direction is wound. Generally, in a packaging section of this kind of medicine packaging apparatus, a package sheet is fed from the roll, and required information is printed thereon by a printing section. The package sheet is then unfolded from the folded state to be opened, and a nozzle section of a hopper is inserted into the opening to introduce one dose of the medicine. Next, the package sheet is sealed (heat-sealed) in a heat sealing section so that the medicine is enclosed (see, e.g., JP 2004-189336 A, JP 2004-284663 A, JP 2004-238026 A, and JP 2002-19737 A)
Upon first startup of the medicine packaging apparatus or at the time of roll replacement, it is necessary to routing a package sheet unrolled from the roll to the heat sealing section through the nozzle section of the hopper and the printing section before starting medicine packaging operation. In other words, in the roll replacement and the like, a length of the package sheet from the printing section to the heat sealing section (length generally equivalent to 5 to 6 packages) functions only for the routing, i.e., the length is not used for medicine packaging and therefore should be discarded, which is not desirable in view of cost. Moreover, the long path of the package sheet from the printing section to the heat sealing section hinders downsizing of the medicine packaging apparatus. Accordingly, reduction in path length from the printing section to the heat sealing section can eliminate a waste of the package sheet caused by the roll replacement and the like and achieve the downsizing of the device. However, merely shortening the path cannot prevent generation of wrinkles on the package sheet in a portion of the heat sealing section. Generation of the wrinkles is particularly notable when the heat sealing section employs a method of heat-sealing the package sheet by passing the package sheet between a pair of heater rollers.
With reference to FIGS. 46 and 47, a two-folded package sheet 1100 is expanded into V shape by an unfolding guide 1106, and reaches a heating roller 102 of a heat sealing section via a nozzle section 1101 of a hopper. The heater roller 102 has a horizontal seal 1103 which seals an opening edge of the package sheet 1100 in the longitudinal direction, and a vertical seal 1104 which seals the package sheet 1100 crosswise from the opening edge to a crease of the package sheet 1100. If the tension applied to the two portions of the two-folded sheet 1100 is unbalanced during application of the vertical seal 1104, one of the portions of the two-folded sheet 1100 sags against the other portion, which tends to generate wrinkles 1105 extending in the longitudinal direction near the horizontal seal 1103. The wrinkles 1105 are assumed to be attributed to such causes as a bulge of the package sheet 1100 generated in putting medicine therein and a difference of tension between the portions of the package sheet 1100 where the horizontal seal 1103 is formed and where the vertical seal 1104 is formed. Such wrinkles 1105 result in poor airtightness due to sealing failure and thereby cause mixture (contamination) of the medicine between adjacent prescriptions.
Patent Documents 1, 2 disclose an unfolding guide 1106 in the shape of a triangular plate with a constant thickness and an unfolding guide 1106 constituted of a plurality of flat planes and having an outline of a generally triangular pyramid shape. However, if the unfolding guides 1106 in such shapes are employed and placed in the vicinity of the printing section to shorten the path length from the printing section to the heat sealing section, the above-mentioned wrinkles 1105 are unavoidably generated on the package sheet 1100.